Stereo-Curvature Aftereffect Is Due to More Than Shape Curvature Adaptation

Abstract

For stereo-curvature aftereffect (sCAE), there is no agreement on whether adaptation occurs at the disparity-specified stage, the percept-specified stage, or both. Additionally, it remains uncertain whether retinal-position-dependent sCAE can be induced by possible adaptation to disparity-specified sources. Our study aimed to investigate the dependency and processing levels of adaptation underlying sCAE using dynamic spherical adaptation stimuli with static fixation. Experiment 1 examined the dependency by dynamically altering the location or size of adaptation stimuli. Experiment 2 investigated the adaptation levels via three sub-experiments: Experiment 2.1 examined how eccentricity influenced adaptation strength using static adaptation stimuli with different eccentricities, Experiment 2.2 tested a hypothesis about adaptation to a percept-specified primitive shape index (PSI) using dynamic size change of adaptation stimuli, and Experiment 2.3 tested another hypothesis on adapting disparity-specified average disparity information (ADI) using dynamic PSI change of adaptation stimuli. The results showed retinal-position-dependent and scale-independent sCAE. In addition to a possible eccentricity effect, the retinal-position dependence can result from ADI adaptation while the scale independence can be attributed to PSI adaptation. Therefore, sCAE is caused by adaptation at both the disparity-specified and percept-specified stages. Additionally, sCAE endows two coexisting adaptation processes with one dependent on retinal position and one independent of retinal position.